(1) Field of the Invention
The present invention relates to an apparatus and a method for generating alternate current, especially to an induction alternating current generator and an induction alternating current generating method for effectually supplying electricity to an automobile.
(2) Description of the Prior Art
Conventionally, a means aiming at improving the efficiency of an alternating current generator on vehicle was presented by a Japanese Patent Laid-Open No. 116610/1979. In the means, on taking notice of much leak magnetic flux between neighboring claw poles, the leak magnetic flux is reduced, consequently, the efficiency of an alternating current generator is increased by filling up binding material including magnetic material such as ion powder polarized in the direction of repelling the leak magnetic flux. Another means aiming at improving the efficiency and of providing permanent magnets in the gaps between the neighboring claw poles was described in a Japanese Patent Laid-Open No. 85045/1986.
However, the former means has the problems described hereinafter because of using binding material including iron powder, that is, the withstanding voltage of an exciting coil in a rotor core is remarkably worsened by adhesion of conductive material to the exciting coil, and since a large quantity of the binding material for keeping sufficient adhesive power is needed, it is difficult to get even the necessary and minimum magnetic power by using the iron powder for repelling the leak magnetic flux in the full excitation of the rotor core. Therefore, by the above-mentioned means, it can not be expected to sufficiently improve the efficiency of an alternating current generator. And the latter means has also the problem that the initial magnetic power of the permanent magnet polarized in the direction of repelling the magnetic flux of the excited rotor core is decreased by the effects of the rotor core magnetic flux and the high temperature atmosphere.